Rupture of the Achilles tendon is a debilitating injury. Achilles tendon ruptures typically occur in men, most commonly in the third to fourth decade of life, during a sporting activity.3 Houshian et al6 reported in Denmark an annual incidence that increased from 18 cases per 100,000 persons in 1984 to 37cases per 100,000 persons in 1996. The ideal treatment of these injuries remains controversial. Satisfactory functional results after operative management have been reported in multiple series; however the considerable risk of complication remains a concern.8,10,11 Nonoperative treatment historically has been associated with a high risk (13 to 30%) of rerupture,3,10 but more recent reports have similar functional results.12 Operative treatment offers the advantage of a lower rate of rerupture but is associated with the risk of wound-related complications.11 The superficial location of the tendon and presence of local soft tissue trauma secondary to injury represent challenges to wound healing and likely contribute to the relatively high wound complication rate after surgical treatment. Regardless of the technique of open repair, a wound complication rate of 7 to 13% and a deep infection rate of 2 to 4% have been reported.4 A recent meta-analysis of data obtained from prospective, randomized studies noted a 4.7% risk of infection.3
Risk factors such as tobacco use,7,11 diabetes mellitus,5,9 steroid use,11,13 and obesity2 all have been associated with an increased rate of wound complications. The purpose of this study is to determine the risk ratio for specific factors associated with wound related complications in a large series of operatively treated Achilles tendon ruptures.
MATERIALS AND METHODS
Between 1978 and 2001, 167 consecutive patients with Achilles tendon ruptures were treated operatively at a single institution. Patients were identified using a computerized diagnosis database. Institutional review board approval was obtained. One patient denied research authorization. Two patients had bilateral nonsimultaneous Achilles tendon ruptures and only the first repair in each patient was included in the study. Clinical data were retrospectively reviewed. Wound complications were documented and classified according to time of occurrence, severity (deep versus superficial), and treatment. Potential risk factors for wound complication including age, gender, time from injury to surgery, use of tobacco, diabetes mellitus (DM), steroid use, and body mass index (BMI) were evaluated.
Descriptive statistics, including means, standard deviations, medians, ranges, frequencies, and percentages, were used. Log-rank tests were used to compare the rates of postoperative wound complications among groups. A p value of 0.05 or less was considered significant for all analyses. Cox proportional hazards models were used to estimate the risk ratio with 95% confidence intervals for each risk factor. The risk ratio was calculated by dividing the rate of wound complications for one group by that for a second group. For example, a risk ratio of 1.0 would mean that the risk of wound complication was equivalent for the two groups; a risk ratio of 2.0 would mean that the risk in one group was twice that of the second group; a risk ratio of 0.8 would mean that the risk in one group is 20% less than the risk in the second group.
Data from 164 consecutive patients (136 men; 28 women) having Achilles tendon repair were analyzed. The mean age was 43 years and the median age was 41 years (range, 17 to 85 years). All patients were followed up to complete wound healing and the mean clinical followup was 41 weeks (range, 3 weeks–16 years).
Seventeen patients (10.4%) developed a wound complication. Twelve patients (7.3%) had superficial skin necrosis and were treated with oral antibiotics and local wound care; subsequently, their wounds healed. Five patients (3%) developed wound-related deep infections. All five of these patients required operative irrigation and debridement and intravenous antibiotics. Two of these patients had Staphylococcus aureus isolated from surgical cultures, and three of these patients had multiple organisms cultured, including Staphylococcus aureus, Pseudomonas, and Enterobacter species (Table 1). Two patients required free muscle transfer for final closure of the wound. At last followup, all wounds were healed completely. No patients required amputation or had persistent infection.
Nineteen patients of the 164 patients (11.6%) had one or more of the primary risk factors studied present at the time of surgery (13 patients, tobacco use; 6 patients, steroid use; three patients, DM). Patients with one or more of these risk factors had a greater (p < 0.0001) rate (8 of 19) of wound complications than patients without risk factors (9 of 145). Patients using tobacco at the time of injury had a greater (p < 0.0001) risk (5 of 13) of wound complication compared with those not using tobacco (12 of 151) (Table 2). Patients using corticosteroids at the time of injury had a greater (p = 0.0005) risk (3 of 6) of wound complication than the nonsteroid use group (14 of 158). Women had a greater (p = 0.04) risk (6 of 28) of wound complication than men (11 of 136).
The use of tobacco (p < 0.0001, risk ratio = 8.1), steroids (p = 0.0005, risk ratio = 6.8), the presence of one or more of the risk factors: tobacco, steroids, or DM (p < 0.0001, risk ratio = 9.8), and female gender (p = 0.0400, risk ratio = 2.7) were all significantly associated with complications (Table 3). Other factors evaluated were age (≥ 50 versus < 50 years), timing of the repair (within 4 weeks of injury versus more than 4 weeks after injury), and BMI ≥ 30. These factors did not show a significant risk for wound complication.
Rupture of the Achilles tendon is a common injury encountered by the orthopaedic surgeon. The injury can be debilitating, and commonly occurs in young, active persons who desire to return to work or sporting activity. Open surgical repair of Achilles tendon ruptures offers the potential for an excellent functional result and a low risk of rerupture if complications can be avoided.3 Wound necrosis can delay or alter rehabilitation, and deep infection can be a devastating complication, requiring repeat surgery and often resulting in a poor outcome.11
Previous studies have reported a substantial risk of wound healing complications with open surgical techniques. Dalton et al4 reviewed complications of Achilles tendon repair and reported a 7 to 13.6% overall rate of wound complications with a 2.5 to 4% rate of deep infection.4 Bhandari et al3 did a meta-analysis on randomized trials comparing operative and nonoperative treatment of Achilles tendon ruptures and reported a 4.7% wound infection rate in patients surgically treated. The 10.4% rate of wound complication and a 3% rate of deep infection found in the patients in the current study are consistent with these previously published reports.
Smoking has been shown to delay wound healing and to increase complication rates in foot and ankle surgery.7,11 Ishikawa et al7 studied the effects of smoking on hindfoot fusions. This study showed a deleterious effect of smoking on bone healing, with higher rates of nonunion in smokers; however, there was no difference in the rate of infection in smokers compared with nonsmokers.7 Pajala et al11 did a retrospective study of patients who had rerupture and deep infections after surgical treatment of Achilles tendon rupture. This study highlighted the association between smoking and wound complications; 33% of patients with infections had a positive smoking history. Our study also reported a risk for wound complication in tobacco users (risk ratio, 8.1).
Steroid use also has been reported to increase the risk of wound healing complications.11,13 Pajala et al11 found an increased risk of deep infection and rerupture in patients taking corticosteroids. We also found corticosteroid use to be a risk factor for wound complications. In the current study, there were six patients who were on oral corticosteroids at the time of their repair. Three of these patients developed a wound complication (risk ratio, 6.8; p = 0.0005).
Multiple reports have documented increased complication rates in patients with diabetes who have ankle injuries.5,9 Flynn et al5 reported a 32% infection rate in patients with diabetes treated for ankle fractures compared with an 8% infection rate in patients who did not have diabetes. McCormick and Leith9 compared a cohort of 26 patients with diabetes with a group of patients who did not have diabetes; the groups were matched for age, fracture type, and treating surgeon. They found a 42% complication rate in the group of patients with diabetes compared with no complications in the patients without diabetes. Because of the limited number of patients with diabetes in this study, a significantly higher complication rate was not reported in patients with only diabetes as a risk factor. However, when diabetes was combined with smoking or steroid use, an increased rate of wound complications was noted.
We found that women had a higher rate of wound complications than men. Women only accounted for 17% of all patients in this study, and 35% of the wound complications occurred in women. Twenty-five percent of the women had one or more risk factors compared with only 9% of the men in the study, which may account for the elevated risk. Nevertheless, female gender was an independent risk factor. The mechanism of injury in most of the women in the study was a trivial injury (such as while walking or tripping), perhaps reflecting the more frail medical status of this cohort. These data are similar to those found in the study by Pajala et al,11 in which complications occurred with more frequency in patients who had Achilles tendon ruptures during a trivial event rather than a higher energy sporting activity.11
Age older than 50 years, late repair (more than 28 days post injury), and BMI greater than 30 (classified as obesity) were also reviewed. There was no association between these risk factors and the development of wound-related complications. However, the trend in every case was towards a higher rate of complications among patients with these risk factors.
This study has several shortcomings, including the retrospective methodology and the long study period, during which operative techniques and medical treatment might have evolved. All surgeries were done using an open approach; however, specific details of the surgical technique and wound closure were not standardized. Some patients were included despite relatively short followup, provided that documentation of complete wound healing was available. Because the goal of this study was to specifically evaluate wound complications and not to determine long-term function or rerupture rate, we think that it was reasonable to include these patients. Only patients having operative treatment were studied. It is possible that many patients were treated nonoperatively at the discretion of the surgeon after analysis of their comorbidities. Therefore, a selection bias may exist and the true rate of wound complications may be higher than the 10.4% reported in this study. We do not think these limitations undermine the ultimate conclusions of the study. This study identifies a considerable risk of wound healing complications in patients who have specific risk factors, including tobacco use, female gender and corticosteroid use. This information can assist the patient and the surgeon when discussing and selecting the best treatment method for acute Achilles tendon rupture. Alternatives to traditional open surgical repair techniques (such as percutaneous repair1 or nonoperative treatment) perhaps should be considered in the subset of patients presenting with risk factors.
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